Recent rapid diffusion of mobile phones is remarkable, and various technologies have been proposed for reducing cost and increasing battery life.
For example, polar modulation which separately processes an amplitude component (AM) and a phase component (PM) does not require a power amplifier with high linearity. Thus, lower cost and lower power consumption can be expected to be realized for a function of transmitter for mobile phones and the like.
Patent literature 1 is an example of a conventional transmitter employing polar modulation.